This invention is in the field of lighting devices, particularly LED lighting, and in particular relates to high intensity LED lighting for film or stage production and other uses, which may include underwater applications. The invention is a versatile light assembly with interchangeable LED heads.
The owner of this invention has several patents on LED lighting devices, particularly for underwater use. See, for example, U.S. Pat. Nos. 9,239,512, 9,188,292 and 8,864,326. In addition, see U.S. Pat. Nos. 8,770,808, 8,733,989, 8,545,069 and 8,070,308, owned by the same assignee and relating to above-ground LED lighting devices.
High-powered LED lights, wherein the LEDs are clustered together, and particularly those that output 4000 lumens, 8000 lumens or even more, face serious cooling issues. In U.S. Pat. No. 8,864,326 an underwater diving light is described having openings for entry of water into the light assembly to contact an LED driver PC board, so that ambient water circulates through the lighting device and cools the LEDs. Above ground, the situation is more critical, since only air is readily available for cooling the LEDs. The LEDs will not perform well and will ultimately degrade if allowed to overheat.
The invention makes changing light color temperature, which is often critical in film and video work, very easy and efficient. In contrast, previous stage lighting has included heads with multicolor LEDs, wherein in 3200K and 5600K light outputs are mixed to create different color temperature output between those two end points. A major problem with this scheme is that at any time, regardless of the color temperature selected, only one half of the LED array may actually be energized, tending toward larger and heavier lights with complex and costly controls. In addition, variable color heads, called in the trade “bi-color”, are notoriously unstable, meaning the active mixing is not highly repeatable and wanders off the setting due the complexity of controlling a large array of LEDs. A fixed head with factory set color temperature is highly stable and maintains its color setting far better than variable controlled LED arrays.